In its offensive towards taking the entire city, the Syrian regime and its allies Monday entered homes and shot dozens of civilians in eastern Aleppo, according to the UN.

"We have been receiving reports of many civilians being detained by pro-government forces. We also have been informed that pro-government forces have been entering civilians’ homes and killing the individuals found inside, including women and children," UN spokesman Rupert Colville told a press conference at the UN in Geneva Tuesday.

"We received reports of pro-government forces killing at least 82 civilians, including 11 women and 13 children," he added.

Colville said the UN does not know the fate of hundreds of men who have been missing more than two weeks after crossing into Syrian regime-held areas of Aleppo.

"The capture by pro-government forces of the remaining parts of the city of Aleppo is imminent. There was extremely heavy bombardment and shelling throughout the day yesterday," he said.

Colville said armed opposition groups reportedly withdrew from a number of neighborhoods in Aleppo Tuesday morning.

"Multiple sources have reports that dozens of civilians were shot dead yesterday in al-Ahrar Square in the neighborhood of al-Kallaseh, and also in Bustan al-Qasr, by government forces and their allies, including allegedly the Iraqi al-Nujabaa armed group," he said.

"Yesterday evening, we received further deeply disturbing reports that numerous bodies were lying in the streets but residents were unable to retrieve them due to the intense bombardment, and their fear of being shot on sight," he added.